1975

5.2

1966

7.3

1971

7.4

1967

5.3

1969

7.0

1977

6.3

1974

6.2

1969

6.1

1977

6.6

1975

5.2

1972

5.4

1976

7.5

1962

6.9

1963

7.2

1972

6.8

1970

7.8

1975

6.7

1975

3.0